Marine lipids such as omega-3 rich triglycerides and omega-3 rich phospholipids can be isolated from a number of different natural sources such as fish, crustaceans, plankton, seals, whales as well as algae using extraction technologies. In addition, they can be prepared industrially using chemical or bio-catalytical methods such as enzyme catalyzed transesterification of crude soy lecithin with fish oil fatty acids [1].
The anti-inflammatory properties of omega-3 fatty acids are well known and the use as an anti-inflammatory agent has been described both for triglycerides and phospholipids [2-3]. Actually, omega-3 fatty acids are famous for their anti-inflammatory properties, and it has been shown that omega-3 fatty acids alleviate the symptoms of a series of autoimmune, atherosclerotic and inflammatory diseases including inflammatory bowel diseases and rheumatoid arthritis [4-6]. Suppression of inflammation has been proposed as one of the strategies to slow down the progress of these diseases. Hence, this invention discloses the effect on marine lipid compositions on the concentration of markers of inflammation such as TNF-α and other cytokines such as interleukin-1β and interleukin 6. In addition, since arachidonic acid (AA) is the predominant precursor of the eicosanoid mediators of inflammatory responses (prostaglandins, thromboxanes and leukotrienes), this invention discloses the reduction of AA level and the improvement in the EPA/AA ratio in different lipid pools in tissues such as in the phospholipids isolated from adipose tissue, heart, testicles, plasma, brain and liver.
The bioavailability of EPA and DHA from fish oil triglycerides have been reported to be high in healthy adults. However, for certain conditions i.e. pathological conditions such as extrahepatic cholestasis and for pre-term infants the absorption can be low. For example it was shown that the absorption of DHA from egg lecithin in pre-term infants was 90% compared to 80% from triglycerides [7]. Absorption of long chain PUFA (AA and DHA) is less (75% and 62%, respectively) than the absorption of C18 PUFA (94%) in pre-term infants [8]. The difference between C18 PUFA and long chain PUFA absorption is likely to become less apparent in older children and adults. Sala-Vila et al [9-10] investigated the bioavailabilities of DHA-PL and DHA-TG in full term infants and found no differences based on plasma lipid enrichments. Valenzuela et al. [11] supplemented female rats with different forms of DHA including egg yolk PL and single cell algae TG. They found also no difference in absorption of DHA from PL and TG based on plasma lipid enrichments. However, the tissue and milk fat levels were higher in PL-DHA compared to the TG-DHA supplemented rats. These data indicate that although there were no differences in the bioavailability, efficacy with respect to tissue enrichment was higher for PL-DHA compared to TG-DHA. Furthermore, the relative absorption of EPA and DHA ethyl esters (4 g/d) compared to oleic acid calculated from peak concentrations was 94 and 100%, respectively. Estimates of relative absorption based on the area under the concentration curve indicated a relative absorption of 91% for EPA and 93% for DHA [12]. Bioavailability of C18:1, C18:2 and C18:3 in adult humans are close to 100% (note 94% in preterm infants). Thus the bioavailability of EPA and DHA delivered in different forms is, according to previous, work likely to be over 90%.